To date, there has been proposed an engine startup device equipped with an electromagnetic switch that can independently perform functions of turning on/off a motor activation circuit and making a moving body jump out. (See Patent document 1, for example.)
In addition, there has been another device that, using the electromagnetic switch described in Patent document 1, synchronizes rotation speed of a moving body with that of a ring gear and following that, makes the moving body jump out so as to engage with the ring gear. (See Patent document 2, for example.)